Field of the Invention
The invention relates to a fuel pressure regulator for insertion into an injection supply system for controlled-ignition internal combustion engines. More particularly, the invention relates to a device regulating the positive pressure with which fuel is introduced into the injectors and keeping it at a constant relation to the pressure in the engine intake manifold in order to maintain the proper ratio of the air/fuel mixture under all operating conditions of the vehicle.
Devices of this kind have long been known and used. They are mechanical assemblies of elements whereby the flow of fuel supplied by a pump is divided into two unequal portions. One portion is supplied to the injectors, which absorb the quantity required under the engine operating conditions, whereas the remainder is returned to the vehicle tank.
The difference between the pressure at which fuel is supplied to the injectors and the pressure in the intake manifold must remain constant in order to ensure that the engine is properly supplied under all operating conditions. Any wear or defects in the manufacture or assembly of the mechanical components of the regulator must not affect the constant difference between the pressure of the fuel reaching the injectors and the pressure in the manifold.
More particularly the said pressure difference must be maintained constant under the various operating conditions even in the case that the diaphragm of the mobile component of the pressure regulator is not parallel to the inlet opening of the pipe system returning excess petrol to the vehicle tank. Such a diaphragm is usually associated with closure means adapted to vary the cross-section area of the petrol flow at the said inlet opening.
The main object of the invention, therefore, is to ensure that the closure means, which moves with the diaphragm, is kept parallel to the inlet plane of the return pipe system even when the plane of the diaphragm is not parallel to the inlet plane, since such parallelism ensures that the aforementioned difference remains constant.